The last pulse of convection phase Madden Julian oscillation (+MJO) was observed during November across the eastern tropical Indian Ocean to north of Australia. The event was immense, causing many late season tropical cyclones, and eventually a latent heat release poleward to the polar stratosphere. In December, the warming stratosphere shifted over Canada igniting an arctic outbreak. Since that time, MJO has been dormant. However, in a forecast change, the 2-week MJO forecast utilizing all models indicates a moderate intensity phase_6 of the +MJO develops which will cause several important impacts on weather and climate.

In the extended range, interesting is the drop-off in skill from 0.25 to 0.45 in the 16-20-day period to 0.15 to 0.25 in the 25-30-day period. In fact, the 25-30-day forecast skill of the popular ECM “weeklies” was matched by the 10-year climatology. Not commonly used for extended range forecasts, GFS ENS ranked first for the extended range outlooks for the past 30 days.

Globally, 2025 projects as the third warmest on record (DEC-25 data not yet available as of this writing). As of December 1st, the U.S. has observed the fifth warmest year in the 131-year period of record. A significant contributor to the warmer climate is the influence of increasing ocean temperature, most notable in the middle latitudes accelerated by the presence of marine heatwaves (MHW).

Last week, the Nino SSTA regions warmed too near, or warmer than the La Nina threshold. Implied is the short duration late 2025 La Nina episode is past peak intensity. Upper ocean heat is steadily diminishing in the equatorial East Pacific, a definite sign that La Nina is losing cool fuel to sustain intensity into the New Year.